Insmed Stock Holds Strong as CFO Bonstein Executes Planned Share Sale

Rhea-AI Filing Summary

Insider Trading Activity Report: Sara Bonstein, Chief Financial Officer of Insmed, executed significant transactions on June 23, 2025, through a pre-planned 10b5-1 trading plan established on March 5, 2025.

Transaction Details:

• Exercised 35,253 stock options at $18.95 per share and 12,636 options at $19.74 per share
• Sold 49,104 shares at weighted average price of $101.71 (range: $101.04-$102.03)
• Sold additional 8,661 shares at weighted average price of $102.15 (range: $102.04-$102.61)

Following these transactions, Bonstein holds 93,536 shares directly, plus remaining stock options including 99,007 at $18.95 strike price and 25,124 at $19.74 strike price. The options vest over four years with 25% vesting on first anniversary and 12.5% every six months thereafter.

Positive

• None.

Negative

• CFO Sara Bonstein executed a significant planned sale of 57,765 shares at weighted average prices of $101.71-102.15, totaling approximately $5.9M, through a 10b5-1 trading plan

Insights

Insider Trading Analyst

CFO Bonstein exercised options and sold shares at significant gain, retaining 93,536 shares after planned transactions under 10b5-1 plan.

Sara Bonstein, Insmed's CFO, executed several transactions through a pre-established 10b5-1 trading plan. She exercised 47,889 stock options (35,253 at $18.95 and 12,636 at $19.74) and subsequently sold 57,765 shares at weighted average prices of $101.71 and $102.15. This represents a significant profit realization given the approximately $82 spread between exercise and sale prices.

After these transactions, Bonstein reduced her direct holdings from approximately 151,301 to 93,536 shares, representing about a 38% decrease in her position. She also still holds 124,131 unexercised stock options (99,007 at $18.95 and 25,124 at $19.74).

The use of a 10b5-1 plan, established in March 2025, indicates these sales were planned well in advance and don't represent reactive selling based on recent company developments. This type of planned diversification is common among executives for personal financial management. The retention of a substantial position (93,536 shares) suggests continued confidence in the company despite the profit-taking.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Bonstein Sara

(Last) (First) (Middle)

700 US HIGHWAY 202/206

(Street)

BRIDGEWATER NJ 08807

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
INSMED Inc [ INSM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
06/23/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/23/2025		M(1)		35,253	A	$18.95	138,665	D
Common Stock	06/23/2025		M(1)		12,636	A	$19.74	151,301	D
Common Stock	06/23/2025		S(1)		49,104	D	$101.71(2)	102,197	D
Common Stock	06/23/2025		S(1)		8,661	D	$102.15(3)	93,536	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$18.95	06/23/2025		M(1)			35,253	(4)	05/11/2033	Common Stock	35,253	$0	99,007	D
Stock Option (right to buy)	$19.74	06/23/2025		M(1)			12,636	(4)	01/05/2033	Common Stock	12,636	$0	25,124	D

Explanation of Responses:

1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on March 5, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.

2. This is the weighted average sales price representing 49,104 shares sold at prices ranging from $101.04 to $102.03 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

3. This is the weighted average sales price representing 8,661 shares sold at prices ranging from $102.04 to $102.61 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

4. The options become exercisable based on the following vesting schedule: 25% vest on the first anniversary of the grant date and an additional 12.5% vest on each sixth month anniversary date thereafter through the fourth anniversary of the date of grant.

Remarks:

	/s/ Sara Bonstein, by Michael A. Smith as Attorney-in-fact	06/25/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider trading activity occurred at INSM on June 23, 2025?

INSM's CFO Sara Bonstein exercised stock options for 47,889 shares (35,253 at $18.95 and 12,636 at $19.74) and subsequently sold 57,765 shares at weighted average prices of $101.71 and $102.15. These transactions were executed under a 10b5-1 trading plan established on March 5, 2025.

How many INSM shares does CFO Sara Bonstein own after the June 2025 transactions?

Following the reported transactions, Sara Bonstein directly owns 93,536 shares of INSM common stock. She also retains 99,007 stock options at $18.95 and 25,124 stock options at $19.74.

What was the total value of INSM shares sold by the CFO in this transaction?

The CFO sold a total of 57,765 shares in two blocks: 49,104 shares at an average price of $101.71 and 8,661 shares at an average price of $102.15. The total approximate value of the sales was approximately $5.9 million.

What is the vesting schedule for INSM's stock options according to the filing?

According to the filing, INSM's stock options vest on the following schedule: 25% vest on the first anniversary of the grant date, followed by additional 12.5% vesting every six months thereafter through the fourth anniversary of the grant date.

Was INSM CFO's stock sale pre-planned through a 10b5-1 trading plan?

Yes, the transactions were executed pursuant to a 10b5-1 trading plan that Sara Bonstein adopted on March 5, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934.